This invention relates to an improved system for protecting a building, a piece of equipment, or a similar superstructure against damage or collapse due to predicted maximum earthquake vibrations. The invention provides stable and controllable performance during an earthquake, with minimum spatial requirements and minimal costs, and is useful both in the construction of new buildings or equipment installations, and when retrofitting existing structures or equipment installations to enhance their earthquake resistance.
Earthquakes present a major public safety hazard. Building occupants and persons on the streets adjacent buildings and other structures are in peril during an earthquake. In addition, earthquakes create a major economic liability for building owners and communities that depend on the continuity of building usage.
Thus, buildings and equipment, as well as people in and around such buildings and equipment, need protection against the effects of structurally damaging forces generated by the random ground movements of earthquakes. My above-identified previous patents disclose various apparatus for providing such protection. The instant invention provides an improved system for such protection, by enhancing stability and controllability as well as minimizing spatial interferences and costs.
Among other things, my U.S. Pat. No. 3,638,377 explains the bases and method for limiting the horizontal transfer of inertial forces between a superstructure and its substructure, and for calculating an anticipated horizontal displacement of that superstructure with respect to its supporting substructure. As set forth below, after that displacement has been calculated, it may be utilized to determine the dimensions required in the aforementioned minimum spatial interference. As further explained below, that calculated displacement is directly related to the "predetermined distance" discussed hereinbelow.